Faculty

Professional Background:B.Sc. Chemical Physics, The University of Toronto 1993M.Sc. Physical Chemistry, The University of Toronto 1994Ph.D. Physical Chemistry, Georgia Institute of Technology 2000Postdoctoral Associate 2002-2005 The University of ChicagoPostdoctoral Associate 2005-2006 NASA Center for Nanotechnology

Research Synopsis:Colloidal nanoparticles are fascinating materials because of their extraordinary flexibility
and their remarkable diversity of properties. They are unique hybrid materials consisting
of a solid inorganic core protected by a soft outer shell of organic molecules. Traditionally,
the building blocks of a chemist have been limited to the known elements, with each
element's properties being fixed. In contrast, we can adjust the properties of nanoparticles by changing almost trivial properties such as core size or type of capping molecules.
In this way, nanoparticles can act like artificial atoms and transcend the periodic table. Such flexibility
promises highly-optimized designer materials for applications as diverse as catalysts,
sensors, magnetic storage media, solar energy capture, lasers, medical probes and
therapeutics.

My laboratory mainly focuses on molecular nanoparticles. As the name suggests, these
are a class of nanoparticles with molecular definition, i.e. they have a precise molecular
formulae and structures. The formulae are typically determined by electrospray ionization
mass spectrometry and the structures are determined by single-crystal x-ray diffraction.
One could also think of this as a new class of organometallic molecules with a large
number of metal atoms in their cores, which would lie between conventional nanoparticles
(which are analogous to polymers) and small organometallic molecules. While conventional
nanoparticle science is highly developed, the synthesis and design of molecular nanoparticles
demands more detailed investigation. Fortunately, their molecular definition enables
rigorous study due to the detailed structural information that is now available, which
guides experiment and theory.

Our research on molecular nanoparticles is focused on three things: (i) developing
new strategies for synthesizing and processing molecular nanoparticles; (ii) understanding
the structure-property relationship for molecular nanoparticles with the goal of molecular
design; (iii) developing new strategies of assembling molecular nanoparticles into
complex and functional nanocomposite materials. Silver has been our metal of choice
since its chemistry and optical properties are richer than those of gold. We also
work with gold and other metals, including for plasmonic nanoparticles, as well as Earth abundant semiconductors for solar energy applications. This research
spans many diverse fields, including physical, inorganic, and organic chemistry, hard
and soft condensed matter physics, and materials, chemical and mechanical engineering.